@Merlin posted:When the great flood IDA hit and tried to save a lot of trains while the water was pouring in a weird thing happened to my track. They were sitting in the water for two days before I was able to wash and dry them off. Sections of the track started to grow black spots on them. It wasn’t brown like regular rust, it was pure black. I tried sanding them down but that didn’t work. I don’t know if that was a chemical reaction to the water or how they rust over time.
Merlin - sounds like some type of black mold.
We used to have a tiled shower that seemed to grow black mold overnight if it wasn't wiped down after every use.